Question

我正在努力并没有并行运行一个巨大的循环。循环恰好是特定类的一种方法，在循环内部我称之为另一种方法。它确实有效，但由于某种原因，列表中只有一个进程，输出（参见代码）始终为“Worker 0”。要么没有创建进程，要么它们没有并行运行。结构如下：

main.py

from my_class.py import MyClass

def main():
    class_object = MyClass()
    class_object.method()

if __name__ == '__main__':
    main()

my_class.py

from multiprocessing import Process

MyClass(object):
    def __init__(self):
        # do something

    def _method(self, worker_num, n_workers, amount, job, data):
        for i, val in enumerate(job):
            print('Worker %d' % worker_num)
            self.another_method(val, data)

    def another_method(self):
        # do something to the data

    def method(self):
        # definitions of data and job_size go here

        n_workers = 16
        chunk = job_size // n_workers
        resid = job_size - chunk * n_workers

        workers = []
        for worker_num in range(n_workers):
            st = worker_num * chunk
            amount = chunk if worker_num != n_workers - 1 else chunk + resid
            worker = Process(target=self._method, args=[worker_num, n_workers, amount, job[st:st+amount], data])
            worker.start()
            workers.append(worker)

        for worker in workers:
            worker.join()

        return data

我已经阅读了一些有关子进程需要主模块可导入的内容，但我不知道如何在我的情况下执行此操作。

Answer 1

问题：...但仍然只有一个核心正在使用中。所以问题是，我可以在Process对象中使用多个核心

这不依赖于Process正在使用哪个CPU的Python解释器相关：on-what-cpu-cores-are-my-python-processes-running

使用以下内容扩展您的def _method(...，以查看实际发生的情况：

注意：getpidcore(pid) 分发 dependend，失败！

def getpidcore(pid):
    with open('/proc/{}/stat'.format(pid), 'rb') as fh:
        core = int(fh.read().split()[-14])
        return core

class MyClass(object): 
    ...
    def _method(self, worker_num, n_workers, amount, job, data):
        for i, val in enumerate(job):
            core = getpidcore(os.getpid())
            print('core:{} pid:{} Worker({})'.format(core, os.getpid(), (worker_num, n_workers, amount, job)))

输出：

core:1 pid:7623 Worker((0, 16, 1, [1]))
core:1 pid:7625 Worker((2, 16, 1, [3]))
core:0 pid:7624 Worker((1, 16, 1, [2]))
core:1 pid:7626 Worker((3, 16, 1, [4]))
core:1 pid:7628 Worker((5, 16, 1, [6]))
core:0 pid:7627 Worker((4, 16, 1, [5]))

使用Python测试：Linux上的3.4.2

在python中的并行进程中运行类方法

1 个答案: